The widespread prevalence of low back pain (LBP) was associated with health care expenditures of $26.5 billion in the U.S. in 1998, as well as with 5.3 hours per week of lost productive work time. Most LBP cannot be attributed to any identifiable anatomic cause, and evidence-based guidelines for its treatment recommend both traditional and alternative therapies - such as spinal manipulation - prescribed by medical doctors (MDs) and doctors of chiropractic (DCs), respectively. Thus, understanding the cost tradeoffs between such therapies in the context of actual patient choice and provider practice patterns is crucial to identifying strategies that promote the efficient use of care for the treatment of acute LBP. Further, patient choice of whether an MD or DC is initially seen hinges on patient access to DCs, which previous research has not addressed. This proposal seeks to address these issues by using administrative claims data in 2004 from Blue Cross & Blue Shield of Rhode Island (BCBSRI), the dominant insurer in the state of Rhode Island. The specific aims of the study are to: [1] describe and compare the patterns of services received for patients with acute uncomplicated LBP episodes by speciality of the initial provider (if MD or DC) and whether a single or multiple providers are used; [2] evaluate the association between patient choice of initial provider type and access to DCs, and whether this choice differs by gender; and [3] evaluate the association between the cost of care per acute LBP episode and choice of initial provider controlling for patient demographic, clinical characteristics, and insurance coverage type, and by using local supply of chiropractors as an instrument to control for initial provider choice which may depend on unobserved LBP severity. [unreadable] [unreadable] Understanding the cost tradeoffs of recommended traditional versus alternative therapies for the treatment of LBP in a real-world setting may suggest that health plans could improve chiropractic coverage or limit the use of some types of services that may contribute to higher costs. Such strategies may help reduce the health care expenditures associated with LBP. The findings from this proposed research will lead to a larger study which would examine outcomes and costs. [unreadable] [unreadable] [unreadable]